Featured image / author gone in WordPress 6.0.2

Hello,

I’m working in my own theme and it randomly stopped working after the 6.0.2 update.
Featured image is gone. Not even visible in the settings menu. And Author is also gone.

I disabled my functions.php, deleted my theme.json, disabled all plugins and redownloaded a clean wordpress installation. So its a clean theme, still no featured image & author dropdown box.

This is the only code in functions.php right now:

function tatof_theme_setup() {
    add_theme_support('automatic-feed-links');
    add_theme_support('post-thumbnails');
    add_theme_support( 'responsive-embeds' );
    add_theme_support( 'disable-custom-colors' );
}
add_action( 'after_setup_theme', 'tatof_theme_setup' );